Combination lock



Nov. 4, 1969 c. E. GERMANTON I 3,475,932

cousxm'rzoupocx Filed March 2 1967 4 Sheets-Sheet 1 INVENTOR C. EGERMANTON By @m v ATTORNEY Nqv. 4, 1969 c. E. GERMANTON COMBINATION LOCK4 Sheets-Sheet 2 Filed March 28, 1967 Nov. 4, 1969 c, 5. GERMANTON3,475,932

COMBINATION LOCK Filed March 28, 1967 4 Sheets-Sheet 3 FIG. 88 I I CAP45 cmca KNOB I8 RETURN DISSIPATED S0 STARTED CANNOT BE USED I? II IIEELAY KNOB I8 RETURN CONTINUED; I I CA N BE RELEASED INTERPOSER 29DEI-LECTED TO ONLY BY. SECMD ENGAGE RADIAL ARM 2| SO ARM COMBINATIONMOVES WITH KNOB I6, LATCH RETRACTED AND ENTRANCE v v GAINED 1 KNOB I8RELEASED; SPRING 22 RETURNS RADIAL ARM 2| AND ON KNOB IS IN ENGAGINGSPRING 3| RELEASES RELEASED STATE INTERPOSE R 29', VANE 24 AND RADIALARM 2| RETURN TO *6 AND H NORMAL POSITIONS CAP 48 CHARGES ATTEMPTABANDONED CAP 42 RECHARGES KEY T TART AGAIN STATE OF DEVICE NORMAL STATEOF DEVICE GIIANGED SPOT SET OF CONTACTS United States Patent 3,475,932COMBINATION LOCK Charles E. Germanton, Summit, N..I., assignor to BellTelephone Laboratories, Incorporated, Murray Hill, N ..I., a corporationof New York Filed Mar. 28, 1967, Ser. No. 626,566 Int. Cl. 1365b 49/02,47/02 US. Cl. 70-278 6 Claims ABSTRACT OF THE DISCLOSURE The outer knobof a door is interlocked with an unlatching member by deflecting aninterposer member. Electrical circuitry is provided to effect deflectionof the interposer member when a predetermined combination of operativesteps is followed and to prevent deflection of the interposer memberwhen a combination of steps other than the predetermined one isfollowed.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to combination locks utilizing electric circuitry.

Description of the prior art Combination locks provide severaladvantages over key-operated locks. With a combination lock, forexample, an authorized person need not be concerned with a key which maybe forgotten or lost. Furthermore, access by an unauthorized person whohas found or stolen a key is eliminated. Still further, combinationlocks are frequently more pick-proof than key-operated locks.

Notwithstanding the above advantages, combination locks have notreceived as widespread use as key-operated locks. This limited useexists for one or more reasons. Many combination locks, for example, arenot sufficiently pick-proof. Furthermore, it is often diflicult orimpossible to change their opening combinations so as to foil persons nolonger authorized. Still further, the costs of reliable combinationlocks are often prohibitive.

SUMMARY OF THE INVENTION An object of the present invention is toprovide one or more of the following features in a combination lock:

(1) To make the lock substantially pick-proof in the sense that almostany combination other than its opening combination renders the locknonresponsive to subsequent applications of the opening combinationuntil a reactivating step has been taken;

(2) Once the lock has become nonresponsive to its opening combination,to be able to reactivate it by using a second combination;

(3) To produce an indication when someone is attempting entry or whenthe lock has been rendered nonresponsive to its opening combination;

(4) T o be able to quickly and easily change the opening andreactivating combinations;

(5) To be able to use the lock in a door latching arrangement which iseasily installed and removed;

(6) To require relatively little electrical energy; and

(7) To require relatively little maintenance.

This and other objects are achieved by the invention in anelectromechanical arrangement that requires particular buttons in a setof pushbuttons and a knob or handle to be operated in a combinationalsequence in order for the lock to be opened. In particular, pushbuttonsare first operated to close an electrical circuit. Closure of thiscircuit causes a first mechanical member to move so that ice a secondmechanical member may move past it when the knob is turned. The knob isthen turned. After it has been turned, other pushbuttons are operated toclose another electrical circuit. Closure of this circuit causes thefirst member to return to its original position. The knob is thenreturned to its original position. In the course of returning the knobto its original position, a cam-like action between the first and secondmembers causes the second member to interlock the knob with the latchingelement of the lock, thus causing a latching element to be released bythe returning knob.

In accordance with the invention, initial movement of the first memberis produced by transferring stored energy from a first capacitor to asecond capacitor. The final movement of the first member is produced bytransferring stored energy from the second capacitor back to the firstcapacitor. When, however, an incorrect combination is followed, theinitial movement of the first member occurs but the stored energy isdissipated so that its return movement cannot occur. Because the returnmovement cannot occur, the cam-like action cannot be produced and thelatching element is not released by the returning latch or knob.

Another feature of the invention permits charge dissipated by followingan incorrect combination to be replaced by the execution of areactivating combination. The lock may then be opened by the openingcombination.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a portion of a doorcontaining a lock embodying the invention;

FIGS. 2 through 5 and FIGS. 6A through 6E are sectional views showingvarious elements of the door lock;

FIG. 7 is a schematic diagram of the circuit employed in the door lock;

FIGS. 8A and 8B are portions of a sequence chart illustrating varioussteps that may be performed and the results produced thereby whenattempting to open the lock; and

FIG. 8C is a diagram showing how FIGS. 8A and 8B should be arranged.

DESCRIPTION OF THE DISCLOSED EMBODIMENT FIG. 1 shows a portion of a door11 in which is mounted a combination door lock assembly 12 that embodiesthe invention. The locked side or outside of door 11 faces the viewer inFIG. 1.

The sectional view of lock assembly 12 shown in FIG. 2 is viewed lookingup into the assembly from the side of the door shown in FIG. 1. Thesectional view shown in FIG. 3 is viewed looking up into the assemblyfrom the other side (that is, the inside) of the door. All of theelements in FIGS. 2 and 3 are in their normal positions.

The assembly comprises an outside plate 13, an inside plate 14 and apair of end plates, only one of which is shown and is identified by thesymbol 15. A shaft 16 and a shaft 17 are mounted in plates 13 and 14,respectively. An outer knob 18 is mounted on shaft 16 while an innerknob 19 is mounted on shaft 17. Also mounted on shaft 17 is a latchtripping arm 20. When mounted in the door, as shown in FIG. 1, this armtrips the latch to rous vane 24 is mounted on shaft 16 and is springloaded by a spring 25 so its normal position is against a stop 26mounted on plate 14. A stop 27 is mounted on palte 13 to limit thedegree of rotation of vane 24.

Vane 24 includes a flange 28 having an L shaped aperture cut therein. Aninterposer member 29 is also mounted on shaft 16 and extends through theaperture in flange 28. A small stop 30 is mounted on vane 24 (see FIG.3) so as to give support to interposer member 29 in a manner which willbecome apparent.

A spring 31 is secured to plate 14 in such a manner that its slopingleading edge forces interposer member 29 toward outer knob 18 when themember is in its position closest to knob 19 and knob 18 is turnedcounter clockwise. On the other hand, when knob 18 is in its extremecounter clockwise position and the member is in its position closest toknob 19, interposer member 29 merely deflects the spring radially asknob 18 is turned clockwise with the result that interposer member 29 isnot displaced with respect to flange 28.

The lock assembly also includes a relay 32 (not shown in the fragmentaryview of FIG. 3) mounted on plate 14. This relay is of the magneticallylatching type whereby a current pulse in a first direction causes therelay to operate and remain operated and a current pulse in the oppositedirection causes the relay to release. An extension arm 33 is connectedto the relay armature. This extension arm has a tapered end which willbe discussed subsequently with respect to the operation of the lock.

A first magnet 34 and a first reed switch 35 are mounted close to stop26 so that vane 24 passes between the magnet and the switch when thevane is held against stop 26. When the vane is between the switch andthe magnet, the switch is in an open, that is disabled, state becausethe magnetic flux cannot pass through the switch. On the other hand,when the va'ne is moved from between the switch and the magnet, themagnetic flux passes through the switch and causes the switch to close.A similar combination comprising a magnet 36 and a reed switch 37 aremounted close to stop 27 so that vane 24 passes between them when thevane is held against stop 27.

Mounted on panel 13 is a container 38 which includes all of the lockscircuitry with the exception of relay 32 and switches 35 and 37.Container 38 includes a plurality of pushbutton-operated switchassemblies which protrude through panel 13 and are generally identifiedby the symbol 39.

Before discussing the electrical circuitry of the lock assembly thefunctions of the above-identified mechanical members are firstpresented.

As mentioned above, all of the mechanical elements are shown in theirnormal positions in FIGS. 2 and 3 and, furthermore, the door may beunlatched by turning inner knob 19. The door can not, however, beunlatched by merely turning knob 18. In particular, as knob 18 isturned, interposer member 29 passes spring 31 and switch 35 closes. Aswill be explained subsequently, the closing of switch 35 causes relay 32to operate. If relay 32 were not operated, interposer member 29 wouldencounter relay armature extension arm 33 and would be deflected asshown in FIG. 6A. Relay 32 remains operated and, as shown in FIG. 6C,knob 18, when released, returns to its normal position without causinglatch tripping arm 20 td'be moved.

In order to move latch tripping arm 20, relay 32 must first be operatedso that interposer member 29 may be moved past extension arm 33 whenknob 18 is turned. The manner in which interposer member 29 passes arm33 is demonstrated in FIGS. 6B and 6C. Once this is accomplished, relay32 must be released as shown in FIG. 6D. When knob 18 is turned back toits original position, interposer member 29 moves toward plate 14 as themember rides up on the sloping portion of extension arm 33. This isshown in FIGS. 4 and 6E. It should be noted that at this point thatinterposer member 29 is on the other side of radial arm 21 and,furthermore, has been moved so that when knob 18 is returned, theinterposer member comes into contact with the radial arm and causes itto rotate with the interposer member. Stop 30 supports the interposermember so that it is not unduly deflected in the process of exerting aforce on the radial arm. As knob 18 returns to its normal position,spring 31 deflects and permits interposer member 29 to pass with theradial arm. Moving the radial arm, of course, rotates shaft 17 whichmoves latch tripping arm 20 to unlock the door.

When knob 18 is released, spring 22, which is stronger than spring 25,causes shafts 16 and 17 to rotate in a direction to return radial arm 21to its normal position. While this is occurring, the sloping front ofspring 31 deflects interposer member 29 which, in turn, moves out ofphysical contact with radial arm 21. Springs 22 and 25 then cause theirrespective shafts to return to their normal positions. The door has thusbeen unlocked and the lock has been returned to its initial state.

The electrical circuit in container 38 and the manner in which it isused to operate and release relay 32 is now presented in conjunctionwith FIG. 7.

For convenience in the following discussion, pushbutton assemblies 39 ofFIG. 2 are identified by the letters A through H and J, respectively. Inthe disclosed embodiment, these assemblies are of the type that areeasily inserted and removed a panel. The opening and reactivatingcombinations are therefore easily changed by merely rearranging thelocations of the assemblies; that is, rewiring is not necessary in orderto change the combinations.

In FIG. 7, an X on a conductor implies a normally open set of contactswhile a short perpendicular line through a conductor implies a normallyclosed set of contacts. This is illustrated in the key in FIG. 7. Theletters A through H and J adjacent to the contact symbols refer to thepushbutton assemblies on which these contacts are located. The presenceof a number next to a set of contacts implies that more than one set ofcontacts are on a pushbutton assembly. Contacts K are contacts on relay32 while contacts K and K are contacts in limit switches 35 and 37,respectively.

For the lock to open in response to its opening combination, all of thecontacts of FIG. 7 must initially be in the states shown. Under theseconditions, a conducting path comprising a resistor 40, contacts K and Kand relay 32 exists between a battery 41 and a capacitor 42. As a resultof this path and battery 41, a charge is stored on capacitor 42 so thatits ungrounded terminal is negative with respect to ground. (Resistor 40limits the charging current so that relay 32 is not operated.)

Further study of FIG. 7 shows a path including a pair of single-poledouble-throw switches which comprise contacts A and B on pushbuttonassemblies A and B. The normally open portions of these switches areconnected in series in this path with their common contacts (that is,their swinger or arm contacts) connected together and their remainingcontacts grounded. When the opening combination is followed, contacts Aare operated and held, contacts B are operated and held and a portion ofthe energy in capacitor 42 passes through relay 32 to capacitor 45.Relay 32 operates and remains magnetically latched in an operatedposition. Contacts A are then released and capacitor 42 discharges itsremaining energy to ground. Contacts B are then released to removeground from relay 32.

FIG. 7 shows another path which includes a similarly connected pair ofsingle-pole double-throw switches which comprise contacts C and D ofpushbutton assemblies C and D. When the opening combination is followed,this path operates in the same manner as the path described in theprevious paragraph and relay 32 is released.

When a wrong combination is used, one of the paths described in the twoprevious paragraphs or one of several other paths functions in a mannerto discharge capacitors 42 and 45 and to leave relay 32 in an operatedstate. The manner in which these various paths function is now presentedin detail.

The manner in which the disclosed embodiment responds to variouscombinations is described below with the help of the sequence chartshown in FIGS. 8A and 8B. This chart is read from top to bottom. Thebroken vertical line on the left shows the actions produced on astep-by-step basis when the opening combination is followed. The linesto the right of this line show the various actions produced whendeviations from the opening combination are made. In reading the chart,a dot at the bottom of a vertical line segment means that it is possiblefor the action to progress from that line segment into any of the otherline segments surrounding the dot. On the other hand, a dot at the topof a vertical line segment means that action on any of the other linesegments surrounding that dot will progress into the vertical linesegment. Furthermore, as indicated in the key, an X indicates a deviceis operated while a perpendicular bar indicates the device is released.

The combination for opening the lock assembly and the results producedthereby comprise (see FIGS. 7, 8A and 8B):

(1) Depressing, and holding depressed, the button of assembly A: When anoptional alarm circuit 43 is present, contacts A cause this alarm to besounded as an alert that someone (either authorized or unauthorized) isattempting entry;

(2) Depressing, and holding depressed, the button of assembly B: A pathis completed from capacitor 42, through relay 32, contacts K B and A aresistor 44 to a capacitor 45. The charge on capacitor 42 is dividedbetween capacitors 42 and 45. The resulting current flow operates relay32 which, in turn, opens the path between battery 41 and capacitors 42and 45 and moves extension arm 33. Relay 32 remains magnetically latchedin its operated state.

(3) Releasing button of assembly A: A path from capacitor 42, relay 32and contacts K B and A to ground is completed and capacitor 42 isdischarged.

(4) Releasing button of assembly B: Grounding path for capacitor 42 isremoved.

(5) Turning outer knob 18 to its other extreme position and holdingthere: Contacts K are closed and contacts K are opened.

(6) Depressing, and holding depressed, the button of assembly C: Ccontacts switched to states other than normal.

(7) Depressing, and holding depressed, the button of assembly D: Dcontacts switched to states other than normal to complete path fromcapacitor 45, through resistor 44, contacts D and C and relay 32 tocapacitor 42. The charge on capacitor 45 is divided between capacitors42 and 45. The current produced thereby releases relay 32. When therelay releases, the alarm is deactivated and extension arm 33 isreturned to its normal position.

(8) Releasing the button of assembly C: C contacts returned to normaland remainder of charge on capacitor 45 is discharged through resistor44 and contacts D and C (9) Releasing the button of assembly D: Dcontacts returned to normal thereby breaking the discharge path forcapacitor 45.

(l0) Returning knob 18- to its original position: Limit switch 37recloses its contacts, thereby completing the path between battery 41and capacitor 42. Interposer member 29 is deflected by extension arm 33and radial arm 21 is engaged and carried along with the interposer arm.Shaft 17 and latch tripping arm 28 are rotated and door is unlocked.

(11) Releasing knob 18: Knob 18 is rotated by spring 22 until spring 31disengages interposer member 29. When interposer member is released, allof the elements return to original positions. When door is closed, it isagain locked. Limit switch 35 is released, thereby removing a ground sothat capacitor 42 is charged from battery 41.

The above steps illustrate how the lock is opened when the openingcombination is followed. A few of the actions produced when the openingcombination is not followed are now considered.

(1) Turning knob 18 before doing anything else (see top horizontal lineof FIGS. 8A through 8B): Limit switch 35 is operated and capacitor 42 isdischarged through relay 32 and contacts K37, C K and B to ground andrelay is operated and remains operated. All of charge is dissipated andcharging circuit is disabled. Alarm is activated. Relay cannot bereleased unless special reactivating combination is used. (This isdiscussed later);

(2) Operating the button of assembly B, C or D before doing anythingelse (see second from top horizontal line of FIGS. 8A through 8B): Aconducting path from capacitor 42 through relay 32 to ground is providedand the charge on capacitor 42 is discharged through the relay. Therelay is operated and remains operated. All of the charge is dissipatedand charging circuit is disabled. Alarm is activated. Relay cannot bereleased unless special reactivating combination is used.

(3) Operating the button of assembly E, F, G, H or J before doinganything else (see second from top horizontal line of FIGS. 8A through8B): A conducting path from capacitor 42, through relay 32 and a diode46 to ground is provided and the same result as described above in 2 isproduced.

(4) Operating the button of assembly A after the opening combination hasbeen followed to the point where the button of assembly A is released:The path comprising contacts A and a diode 47 is enabled and the chargein capacitor 45 divides between capacitors 42 and 45. Charge incapacitor 45 is dissipated to level where it cannot subsequently producecurrent necessary to release relay 32. Alarm remains activated. Relaycannot be released until reactivating combination is used.

(5) Operating button of assembly E, F or I after the opening combinationhas been followed to the point where the button of assembly A has beenreleased: The charge on capacitor 45 is discharged to ground by way of adiode 48. Alarm remains activated. Relay can be released only byreactivating combination.

Other actions that result in failure are believed readily apparent fromthe sequence chart.

From the above discussion, it is apparent that an incorrect operation ofthe pushbuttons or knob 18 causes relay 32 to operate and, furthermore,discharges capacitors 42 and 45 so that energy is not available torelease the relay. The disclosed embodiment will not, therefore, respondto a subsequent application of the opening combination because of theabsence of releasing energy. In accordance with a feature of theinvention, the embodiment is reactivated so as to respond to the openingcombination by using a second combination that releases the relay andrestores the embodiment to its normal state. This feature is nowdiscussed in detail.

To reactivate the lock, knob 18 must first be in its normal position.The buttons of assemblies G and H are then depressed and held for ashort period. This permits battery 41 to place a charge on a capacitor48 by way of a resistor 49. The button of assembly I is then depressedand the charge in capacitor 48 is divided between capacitors 48 and 42.The current flowing during this division causes relay 32 to release andthe path between battery 41 and capacitor 42 is again conductive. Thebuttons of assemblies G, H and J are then released. After a shortcharging time for capacitor 42, the lock is reactivated;

that is, it is in its original state so that the latch can be withdrawnin response to the opening combination.

Although it is not shown in the drawings, a mechanical arm may beafiixed to shaft 17 so that relay 32 is physically released when insideknob 19 is turned. This will cause the lock to be reactivated whensomeone inside answers the door upon hearing the alarm.

Although only one embodiment of the invention has been disclosed anddescribed in detail, various other embodiments may be produced withoutdeparting from the spirit and scope of the invention.

What is claimed is:

1. In combination first and second members normally movable with respectto one another,

an interposer member mounted on said first member and movable therewithin a first path between first and second positions,

first means in said first path blocking movement of said interposermember from said first to said second positions,

second means directing said interposer member moving from said secondposition toward said first position into a second path to engage saidsecond member to move said second member with said first member, and

third means to move said first means out of said first path.

2. A combination in accordance with claim 1 in which said third meanscomprises a magnetic latching relay having a coil and a set of normallyclosed contacts, and

said combination further comprises first and second limit switches whichare open only when said interposer member is in its first and secondpositions, respectively,

first and second capacitors each having first and second terminals,

a source of direct current potential which source has first and secondterminals,

a point of reference potential connected to said second terminals ofsaid capacitors and said second terminal of said source,

a first path connected from said source first terminal to said firstcapacitor first terminal which path comprises said relay contacts, saidsecond limit switch and said relay coil in that order,

a second path connected between said second capacitor first terminal andthe junction of said second limit switch with said relay coil, and

a third path connected between said second capacitor first terminal andthe junction of said relay contacts with said second limit switch,

said second and third paths each including a respective pair of switcheswhere each switch has a pair of normally open contacts and at least oneswitch in each pair is a single-pole double-throw switch,

each pair of said switches connected in its path so that said normallyopen contacts are connected in series in the path, the common contactson the single-pole double-throw switches are connected to their adjacentswitches, the remaining contacts on said singlepole double-throwswitches are connected to said point of reference potential, asingle-pole doublethrow switch in said second path is connectedelectrically nearer to said relay coil than the other switch in saidsecond path and a single-pole double-throw switch in said third path isconnected electrically nearer to said second capacitor than the otherswitch in said third path.

3. A combination in accordance with claim 2 in which all of saidswitches are single-pole double-throw switches,

fourth and fifth paths are connected between said second capacitor firstterminal and the junction of said relay coil with said second limitswitch,

said fourth path including a normally open switch which is closed at thesame time of closing of said normally open contacts on said second pathswitch closer to said relay coil,

said fifth path including said first limit switch and a single-poledouble-throw switch where said first limit switch is serially connectedin said path between the common contact on said last mentioned switchand said relay contacts, the normally open contacts of said lastmentioned switch are connected in series in said fifth path, thenormally closed contacts of said last mentioned switch are connected tosaid reference potential and said last mentioned switch is operated atthe same time as said third path switch closer to said second limitswitch,

a diode connected between said first capacitor first terminal and thecommon contacts of said switches in said third path and poled for chargetransfer from said second capacitor to said first capacitor, and

a normally open switch connected between said point of referencepotential and said junction between said relay contacts and said secondlimit switch and operated at the same time as said second path switchclosest to said second capacitor.

4. A combination in accordance with claim 3 which further comprises asixth path connected in shunt with said relay contacts and comprising aplurality of switches which when operated in a predetermined sequencecause a releasing current to pass through said relay coil, and

a seventh path connected in shunt with said third, fourth and fifthpaths to produce a completed circuit to said point of referencepotential when said switches in said sixth path are not operated in saidpredetermined sequence.

5. A combination lock circuit comprising a magnetically latching relayhaving a coil and a pair of normally closed contacts,

first and second capacitors,

a source of direct current potential connected in series with said relaycontacts and said first capacitor to place energy in said firstcapacitor when said relay is in its released state,

a first path comprising a pair of switches to discharge said firstcapacitor with a portion of said energy being transferred to said secondcapacitor by way of said relay coil and the remainder of said energybeing dissipated when said switches are operated and released in apredetermined sequence and, furthermore, to dissipate all of said energyby way of said relay coil when said switches are operated and releasedother than in said predetermined sequence,

a second path comprising a second pair of switches to discharge saidsecond capacitor with a portion of the energy therein being transferredto said first capacitor by way of said relay coil and the remainder ofthe energy being dissipated when said second pair of switches areoperated and released in a predetermined sequence after said first pairof switches are operated and released in their predetermined sequence,to dissipate energy in said first capacitor by way of said relay coiland to dissipate energy in said second capacitor when said second pairof switches are operated in the wrong sequence and, furthermore, todissipate energy in said first capacitor by way of said relay coil whensaid switches are released in the wrong sequence.

6. A combination lock circuit comprising a magnetically latching relayhaving a coil and a set of normally closed contacts,

first and second capacitors each having first and second terminals,

a source of direct current potential which source has first and secondterminals,

a point of reference potential connected to said second terminals ofsaid capacitors and said second terminal of said source,

a first path connected from said source first terminal to said firstcapacitor first terminal which path comprises said relay contacts andsaid relay coil in that order,

a second path connected between said second capacitor first terminal andthe extremity of said relay coil closer to said relay contacts, and

a third path connected between said second capacitor first terminal andthe one of said relay contacts closer to said relay coil,

said second and third paths each including a respective pair of switchesWhere each switch has a pair of normally open contacts and at least oneswitch in each pair is a single-pole double-throw switch,

each pair of said switches connected in its path so that said normallyopen contacts are connected in series in the path, the common contactson the single-pole double-throw switches are connected to their adjacentswitches, the remaining contacts on said single- References Cited UNITEDSTATES PATENTS 3,266,276 8/ 1966 Yulkowski 70-110 3,170,093 2/ 1965Gilbert 317-135 3,201,658 8/1965 Reynolds 317151 3,326,024- 6/1967Dreyfus, et al 70-351 MARVIN A. CHAMPION, Primary Examiner R. L. WOLFE,Assistant Examiner US. Cl. X.R.

